Late gestation supplementation of feed additives, such as rumen undegradable intake protein (RUIP), vitamin E, Zn, and chlortetracycline, has inconsistently improved ewe/lamb productivity. In 3 experiments, Western white-faced ewes were supplemented for at least 30 d during late gestation with 204 g/(ewe.d) on a DM basis of high (HS; 12.5% RUIP, 880 IU/kg of vitamin E, 176 mg/kg of Zn supplied ...